1. Field of the Invention
The present invention relates to nozzles for use in subterranean earth boring drill bits and drill bits so equipped and, more particularly, to nozzles capable of various angles of adjustment to direct drilling fluid to different locations on and around the drilling apparatus.
2. State of the Art
Subterranean drilling operations generally employ a rotary type drill bit that is rotated while being advanced through rock formations. Elements on the face of the drill bit cut the rock while drilling fluid removes formation debris and carries it back to the surface. The drilling fluid is pumped from the surface through the drill stem and out through one or more, and usually a plurality of, nozzles located on the drill bit. The nozzles direct jets of the fluid to clean and cool cutting surfaces of the drill bit and for the aforementioned debris removal.
Because of the importance of the cooling and cleaning functions of the drilling fluid, others in the field have attempted to optimize these benefits by specifically orienting the nozzle exit to direct the drilling fluid to a predetermined location on a cutting surface of the bit. For example, U.S. Pat. No. 4,776,412 describes a nozzle assembly designed to resist rotational forces while directing drilling fluid to a predetermined rotational position. The nozzle""s internal chamber is preformed to direct the fluid at a specific angle. Likewise, in U.S. Pat. No. 4,794,995, a nozzle is disclosed that changes the direction of fluid flow by angling the exit of the nozzle chamber. Again, the angle of exit is predetermined and may only be rotated about its longitudinal axis. U.S. Pat. No. 4,533,005 is another example of an attempt to provide a nozzle that may be reoriented to provide fluid flow in a specific direction. However, similar to other attempts, once the nozzle has been manufactured, the nozzle angle with respect to the longitudinal axis of the nozzle may not be changed.
The limited ability to adjust state of the art nozzles of a drill bit to accommodate desired fluid directions necessarily limits the amount of positioning or adjustment that can be attained to accurately establish a desired angle of fluid flow, and therefore limits the potential efficiency of the cleaning and cooling functions of the drilling fluid. The ease of manufacture of such nozzles is also limited because for every desired angle, the prior art systems require manufacture of another nozzle. Thus, it would be advantageous to provide a nozzle for use in subterranean earth boring drill bits which provides variable orientability of the nozzle relative to, but independent of, the orientation of the nozzle assembly in the drill bit. It would also be advantageous to provide a nozzle design that does not require a separately manufactured nozzle for every desired angle of drilling fluid flow.
In accordance with the present invention, a nozzle and a system for mounting the nozzle provide modifiable orientation of the nozzle relative to a drill bit to enable accurate and efficient cleaning and cooling of the bit and its cutting structure by drilling fluid passing through the nozzle during subterranean earth boring operations.
According to the invention, a nozzle is structured to be adjustably orientable relative to a surface on a drill bit. The nozzle is thereafter secured into a nozzle orifice on the drill bit. That is, the nozzle orientation may be adjusted relative to the drill bit surface until a desired angle of fluid flow is achieved, then the nozzle is secured into the nozzle orifice of the drill bit. The nozzle is structured to permit a plurality of orientations with respect to the drill bit surface.
The nozzle comprises a nozzle body and a housing that secures the nozzle body within the nozzle orifice and provides the orientability feature of the present invention. The nozzle body may be spherical or tapered on its outer surface and includes a fluid passageway formed within. The nozzle may be formed of any suitable material with adequate abrasion and erosion resistance, such as tungsten carbide, or ceramics. Alternatively, the nozzle passage may be lined with such a material. The adjustable nozzle may be preferably removably secured within the nozzle orifice by suitable mechanical means known in the art including threaded sleeves or retainers or permanently secured therein by brazing, adhesive bonding, or welding. Thermally activated adhesives or metal bonding agents may be especially suitable for use, as easily activated by a torch.
In one preferred embodiment, the nozzle body is secured to a threaded sleeve at a predetermined angle during the manufacturing process. The may be secured by adhesive bonding, welding, brazing, or other means known in the art. The nozzle""s threaded sleeve may then be inserted into the nozzle orifice with the nozzle positioned toward the cutting surface at the desired angle. A distinct advantage of this configuration is the ease in manufacturing a single nozzle body, rather than complex configurations requiring manufacture of various exit angles within the nozzle body.
In another preferred embodiment, the fluid passage of the nozzle is formed into a spherically shaped nozzle body. The spherically shaped nozzle body is then secured into the nozzle orifice by a number of threaded and/or non-threaded sleeves. These sleeves secure the nozzle body into the nozzle orifice at a desired angle. Thus, a single nozzle assembly may be used at several locations on the drill bit, each oriented to better clean and cool the drilling apparatus.
Finally, in another preferred embodiment, the nozzle body""s external periphery is tapered toward the exit port of the nozzle body. The nozzle body is then secured in the nozzle orifice by sleeves that orient the nozzle body and thus the direction of fluid flow. That is, the surface of the sleeve that is in contact with the nozzle body provides the desired angle. This embodiment eliminates the costly manufacture of variously angled nozzle passages within the nozzle body. This, and other advantages of the present invention, will become apparent from the following detailed description, the accompanying drawings, and the appended claims.
Methods of orienting and securing nozzle assemblies according to the present invention are also contemplated as included within the invention as well as tools for effecting such orientation and securement.